Method for encoding/decoding image signal and device for same

Abstract

An image decoding method according to the present invention includes: a step for determining a reference sample line of a current block; a step for determining whether candidate intra-predition modes identical to the intra-prediction mode of the current block exist; a step for deriving the intra-prediction mode of the current block on the basis of the determination; and a step for performing intra-prediction on the current block on the basis of the reference sample line and the intra-prediction mode. Here, at least one of the candidate intra prediction modes may be derived by adding or subtracting an offset to or from the maximum value among the intra-prediction mode of a neighboring block that is above the current block and the intra-prediction mode of a neighboring block that is to the left of the current block.

What is claimed is: 
     
         1 . A video decoding method comprising:
 determining a reference sample line of a current block;   deriving an intra prediction mode of the current block based on whether a candidate intra prediction mode is a same intra prediction mode as the intra prediction mode of the current block; and   performing intra prediction on the current block based on the reference sample line and the derived intra prediction mode,   determining whether to partition the current block into a plurality of subblocks, wherein   when the current block is partitioned into a plurality of subblocks, a type of a horizontal direction transform kernel of a subblock is determined based on a width of the subblock, and a type of a vertical direction transform kernel of the subblock is determined based on a height of the subblock.   
     
     
         2 . The method according to  claim 1 , wherein when a difference between an intra prediction mode of a top neighboring block and an intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value. 
     
     
         3 . The method according to  claim 1 , wherein
 the plurality of subblocks shares one intra prediction mode.   
     
     
         4 . The method according to  claim 1 , wherein inverse transform is omitted for some of the plurality of subblocks. 
     
     
         5 . A video encoding method comprising:
 determining a reference sample line of a current block;   deriving an intra prediction mode of the current block based on whether a candidate intra prediction mode is a same intra prediction mode as the intra prediction mode of the current block; and   performing intra prediction on the current block based on the reference sample line and the derived intra prediction mode,   determining whether to partition the current block into a plurality of subblocks, wherein   when the current block is partitioned into a plurality of subblocks, a type of a horizontal direction transform kernel of the subblock is determined based on a width of a subblock, and a type of a vertical direction transform kernel the subblock is determined based on a height of the subblock.   
     
     
         6 . The method according to  claim 5 , wherein when a difference between an intra prediction mode of a top neighboring block and an intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value. 
     
     
         7 . The method according to  claim 5 , wherein
 the plurality of subblocks shares one intra prediction mode.   
     
     
         8 . The method according to  claim 5 , wherein transform is omitted for some of the plurality of subblocks. 
     
     
         9 . A decoder, comprising:
 a memory, for storing instructions executable by a processor, the processor, for performing the instructions to execute operations of:   determining a reference sample line of a current block;   deriving an intra prediction mode of the current block based on whether a candidate intra prediction mode is a same intra prediction mode as the intra prediction mode of the current block; and   performing intra prediction on the current block based on the reference sample line and the derived intra prediction mode,   determining whether to partition the current block into a plurality of subblocks, wherein   when the current block is partitioned into a plurality of subblocks, a type of a horizontal direction transform kernel of the subblock is determined based on a width of a subblock, and a type of a vertical direction transform kernel of the subblock is determined based on a height of the subblock.   
     
     
         10 . The decoder according to  claim 9 , wherein when a difference between an intra prediction mode of a top neighboring block and an intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value. 
     
     
         11 . The decoder according to  claim 9 , wherein
 the plurality of subblocks shares one intra prediction mode.   
     
     
         12 . The decoder according to  claim 9 , wherein inverse transform is omitted for some of the plurality of subblocks. 
     
     
         13 . An encoder, comprising:
 a memory, for storing instructions executable by a processor,   the processor, for performing the instructions to execute operations of:   determining a reference sample line of a current block;   deriving an intra prediction mode of the current block based on whether a candidate intra prediction mode is a same intra prediction mode as the intra prediction mode of the current block; and   performing intra prediction on the current block based on the reference sample line and the derived intra prediction mode,   determining whether or not to partition the current block into a plurality of subblocks, wherein   when the current block is partitioned into a plurality of subblocks, a type of a horizontal direction transform kernel of the subblock is determined based on a width of a subblock, and the vertical direction transform type of the subblock is determined based on a height of the subblock.   
     
     
         14 . The encoder according to  claim 13 , wherein when a difference between an intra prediction mode of a top neighboring block and an intra prediction mode of a left neighboring block is 64, at least one among the candidate intra prediction modes is derived by adding or subtracting 2 to or from a maximum value. 
     
     
         15 . The encoder according to  claim 13 , wherein
 the plurality of subblocks shares one intra prediction mode.   
     
     
         16 . The encoder according to  claim 13 , wherein transform is omitted for some of the plurality of subblocks.